Divorce biome lib and cleanup code (#11)

* make it boot without biome lib

* make luacheck semi sane

* make fast growth saplings work

* make fast saplings respect nodes there growing on

* make regualr saplings work

* fix some luacheck warnings

* add github actions for luacheck

* bump luacheck line limit, as to gracefully handle long tree rules

* switch over to inline luacheck length rules

* fix screenshot warning

* make tree generation work

* add settings from last night

* comment out new biome lib nonsense added

* tune spawning to be better

* turn down fallback ratio

* translate new abm patch to not use biome lib

* add ethereal since its still behaving badly :(

.github/workflows/luacheck.yml

@@ -0,0 +1,18 @@
+
+name: luacheck
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: apt
+      run: sudo apt-get install -y luarocks
+    - name: luacheck install
+      run: luarocks install --local luacheck
+    - name: luacheck run
+      run: $HOME/.luarocks/bin/luacheck ./